Tandy 1000 platform

Hardware theme

Tandy boasted a percentage of IBM-PC compatibility. This percentage fluctuated. A lot of companies simply made 'Tandy 1000' editions of their PC games


The first video game about Tandy 1000 platform was released in 1982.

RufusPro Software, Sierra On-Line and The Learning Company has published most of these games

CPU: Intel [email protected] ([email protected] in later models, still later [email protected])
RAM: 128K (shared with 2k-128k video, expandable to 640K, 9MB for later models)
OS: IBM PC-DOS 2.10 in 64K? ROM (will also boot from cassette, disk, Later models came up to DOS 3.3. Last models used 132K EEPROM for combined ROM and BIOS and DOS 6.22 could be burned in)
Text modes: 40×25x16, 80×25x16
Graphics 320×200×4, 640×200×2, 160×100×16, 160×200×16, 320×200×16, 640×200×4, Later 640×400×16, still later 800x600x16.
Ports: CGA+/EGA+ D-9 (TGA, later ETGA, still later HD-15 SVGA),RGB, composite video, TV, line-out audio, wired keyboard 8-pin DIN, two joystick 6-pin DIN (8-pin mini-DIN in later models, nearly standard DB-15 ports in last models), printer (edge-card parallel port. external 5½, 3¼, and hard drives were later created for this port. this port was later replaced with a standard, bi-directional parallel port), cassette port (removed on later models), lightpen (later replaced with an D-9 RS-232 serial port), PS/2 type keyboard and mouse ports (not PS/2 compatible, but the last models were PS/2)
Expansion: 7 XT-bus pin slots, 1 external XT-bus pin slot (later models added two 16-bit ISA slots).
Media:5¼ DD 360k disk drive (optional 2nd 5¼ DD disk drive), (3½ DD 720k disk drives were available in later models), (later models came with a 10-20MB hard drive, still later models included an IDE connector for up to 2 IDE drives)
DeskMate 1.0 in ROM (up to 3.0 in later models)

The Tandy 1000 is basically an 8-bit XT-class IBM PCjr clone with enhancements. But the Tandy 1000 lacked the PCjr's cartridge bus. PCjr cartridges cannot be run on a T1k.
Some games were made in Tandy editions that likely did not run on IBM-PCs (especially if there was also an 'IBM version'). Other games were IBM-PC based and had settings to make it 'Tandy Compatible'. Rarely would a PC game run on a T1k without configuring. "Tandy sound" and "Tandy Graphics" settings were very popular for games before the 486 era for PC games that also ran on the Tk1. Since Tandy 1000 models never came with 486 or later CPUs, "Tandy compatible" games virtually disappeared before the Pentium era.
The Tandy 1000 was much more successful than the PCjr, in fact the PCjr was discontinued soon after release but Tandy 1000 models continued for decades. The final models were 16-bit 386 based.
PC Enterprises' GameMaster card was created to 'upgrade' the existing PCjr to be Tandy 1000 compatible. There is also a mod to accomplish this upgrade for users willing to do some soldering. The joystick ports are not PCjr compatible. The PCjr used different proprietary game port than a standard PC. Tandy Coco, TRS-80 and Tandy 1000 used 6-pin DIN game ports and later models of the T1k used 8-pin mini-DIN ports (backward compatible using a 6-pin adapter). Adapters to use standard PC joysticks were available for the T1k and PCjr. Later T1k models used DB-15 gameports that were almost standard (basic 2-axis-2-button joysticks work, hats and extra buttons might cause problems, hats and extra buttons will probable not work even if they don't cause problems). TRS-80 joysticks are 100%. The T1k lacked the PCjr's infrared port for which no accessories were ever released. Both systems use the PCjr expansion bus with 1 external 'sidecar' port. However, the IBM used edge-card slots while the T1k and PCjr used pin sockets. Adapters were common. Generally they can use the same expansion cards, although the T1k has 8 (generally 5 usable) while the PCjr had less since video, drive controllers, and other functions were built-in to the T1k mother board while the IBM often needed as many 5 cards to do what the T1k did on the mother board. 8-bit ISA cards could be used with adapters and 'sidecars'. Later models added 2 standard 16-bit ISA slots. Standard D-15 PC gameports can be added with expansion cards and PC joysticks generally then work with any T1k joystick compatible game. Later models included 2 nearly standard DB-15 game ports. The T1k will accept the same math co-processors as PC/XT and PC/AT motherboards. The first T1k motherboards had no integrated hard disk controller as hard drives were considered high-end and the T1k was a budget PC, like the PCjr was designed to be. The enhanced T1k sold for less than the PCjr. MS-DOS was built into the ROM which combined with no hard drive effectively limited DOS compatibility although it could boot other version of MS-DOS from disk (up to 6.22) and run booterloader games. MS-DOS 4.0 was sabotaged by Microsoft and would not function on most T1k models (like many PC clones, the targets of the sabotage). Ironically, all IBM PC-DOS 4.0 versions could be made to work. It had audio, composite video, RGB, and TV out jacks. Video and TV out was of very poor quality. The TGA/ETGA port was a standard D-9 port that worked on any CGA/EGA monitor. Despite later models having a 80286 CPU, the bus and memory of the T1k remained 8-bit and it would not run in protected mode (it was only windows compatible in real mode). The last models were fully 16-bit. The 8-bit presented the largest barrier for compatibility. XT-bus VGA, 8-bit ISA VGA, or 16-bit ISA SVGA cards could be added, but this was mainly to run IBM games not T1k games. The T1k had no dedicated video memory and used the standard RAM. This allowed higher resolutions and colors that other IBM compatibles of the day. But this took memory from the main program and video updates were slower. Later models dedicated some of the RAM to video but this was just reserved RAM rather then video memory. DOS programs that needed 640K required a T1k with 768k of memory so the video would have the minimum 128k. Non-standard cards could add memory via the XT-bus, including XMS and EMS, but these were usually made for specific software and not general use. OR standard 8-bit LIM EMS memory could be used, but standard memory and non-standard LIM would conflict with each other, only one or the other could be used. Later models used EEPROM for ROM and BIOS that allowed for upgrades (or downgrades) to the built-in operating system and applications. The EEPROM models finally allowed users to customize the boot process so they could leave bootable media in without being forced to boot it.


4=Button 1
5= +5V
6=Button 2

Sierra was hired to create games to show off the PCjr's capabilities. They created King's Quest and began working on many other games for the system. Then IBM dropped support for the PCjr. Sierra was concerned that this might bankrupt them, but they were rescued by Tandy 1000 that could run their PCjr games.

The Tandy could boot to MS-DOS prompt in under 2 seconds. Upgrades were offered that decreased this even more. Some T1k models could be underclocked as slow as 4.77z for backward compatibility.